Table 2.
Risk factors for loss of amputation-free survival at 90 days
| Risk factor | Univariable analysis | Multivariable analysis* | ||
|---|---|---|---|---|
| HR (95% c.i.) | P | HR (95% c.i.) | P | |
| Acute kidney injury† | 6.68 (4.40,10.13) | <0.001 | 5.21 (3.40,8.00) | <0.001 |
| Additional revascularization | 1.58 (1.00,2.50) | 0.051 | – | – |
| Blood transfusion | 2.41 (1.29,4.49) | 0.006 | 1.29 (0.67,2.47) | 0.450 |
| CKD (eGFR <30 ml/min/1.73 m2) | 2.00 (1.08,3.74) | 0.028 | – | – |
| DOACs | 1.65 (1.08,2.53) | 0.020 | – | – |
| Heparin at diagnosis | 1.55 (1.01,2.37) | 0.043 | – | – |
| No revascularization | 3.56 (1.91,6.65) | <0.001 | 2.73 (1.41,5.29) | 0.003 |
| Occlusion aorta | 3.29 (1.81,6.00) | <0.001 | 1.89 (0.96,3.73) | 0.067 |
| Occlusion crural | 1.88 (1.27,2.79) | 0.002 | 1.36 (0.85,2.17) | 0.197 |
| Re-intervention due to bleeding | 2.14 (0.99,4.59) | 0.052 | – | – |
| Rutherford grade III ALI | 3.07 (1.97,4.80) | <0.001 | 2.19 (1.36,3.51) | 0.001 |
| Smoking (active and previous) | 1.58 (1.03,2.45) | 0.038 | – | – |
| Traumatic ALI | 4.03 (1.28,12.72) | 0.017 | – | – |
| Three or more levels of occlusion | 2.93 (1.97,4.35) | <0.001 | 1.94 (1.18,3.16) | 0.008 |
| Wound infection | 1.74 (0.97,3.10) | 0.062 | – | – |
| Wound re-intervention | 1.79 (1.08,2.97) | 0.024 | – | – |
*Variables identified in univariable analysis (P ≤ 0.010) were included in a multivariable Cox proportional hazards model for associations with loss of amputation-free survival at 90 days. †Injury or higher—according to the RIFLE (risk, injury, and failure, sustained loss and end-stage kidney disease) criteria. CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate (calculated using the CKD-EPI equation); DOACs, direct oral anticoagulants; ALI, acute lower limb ischaemia.